Certain well operations, such as well intervention using coiled tubing injection, require a lift frame to position equipment above the wellhead and structurally support the equipment while well operations are being performed. When well operations are performed offshore, the lift frame may include motion compensating systems to account for heave of the drilling platform or vessel.
With conventional methods of well operations, a tubular string or other equipment is hung from bail points, typically located at the bottom or near the lower end of the lift frame. However, due in part to developing technology and increasing variance of well intervention equipment, for certain operations the string or other equipment is hung through a vertical slot formed in the lift frame itself, typically in a lower section of the lift frame.
Hanging equipment through the lift frame slot requires a safety device that secures the equipment to the lift frame. One common safety device involves a door that may be linearly slid across the lift frame slot to cover it. Such a safety door typically does not contact the intervention string or equipment when shut, thereby potentially allowing the string or equipment to shift within the slot and create large dynamic forces against the door.
It is desirable, therefore, to provide a lift frame having a clamping device that contacts the string or equipment to secure it within the vertical slot for such operations.